Vehicle suspension systems are designed to enable the vehicle to ride smoothly and to allow the driver to keep the vehicle under control on bumpy, rough, and hazardous roads and trails. Suspension systems are used in such diverse vehicles as automobiles, motorcycles, four-wheel all-terrain vehicles, trucks, etc.
The suspension systems are attached to the vehicle frame and affect the ride of the vehicle by mitigating the effects of rough roads and trails on the frame. No matter what type of vehicle is used, one challenge to suspension systems is to prevent the vehicle from bouncing too high when it travels over large bumps or emerges from a dip or depression in the road or trail. One problem with current suspension systems is that shock absorbers in the suspension system absorb upward movement from bumps thereby pushing the vehicle upward significantly before the passive pull of gravity brings the vehicle back down toward the road. This can create a safety issue especially with two wheel vehicles such as motorcycles as the relatively light weight of motorcycles allows a greater upward movement to the point of creating a situation in which the motorcycle is airborne.
U.S. Pat. No. 5,226,674 to Buell, et al. discloses a suspension system for a bicycle or motorcycle that includes a single shock absorber attached to the vehicle frame. Although it acts on the rear wheel, it has no effect on the front wheel of the vehicle and no stability for the steering column of the machine. Additionally, Buell, et al., teach the use of multiple pivot axes. U.S. Pat. No. 7,896,379 to Nagao, et al. discloses a front suspension system in which the single shock absorber is pivotally attached to the motorcycle frame. This configuration will cause the vehicle to move upward significantly before gravity pulls the frame downwardly. U.S. Pat. No. 4,189,168 to Courtney relates a wheel suspension system that includes only a single shock absorber on each of the front and back wheels with no immediate direct downward pull by the shock absorber on the front of the frame.
Thus, it can be seen that the field lacks a suspension system that provides a direct active downward movement on a vehicle frame and also provides more than one shock absorber for the wheels of two wheeled vehicles that still provide a direct downward movement on the frame of the two wheeled vehicles utilizing a single pivot axis.